Add Unit Tests with Jest and TypeScript

[francemazzi]

We need to improve the reliability and maintainability of this project by adding unit tests. The goal is to set up Jest with TypeScript and write comprehensive tests for the existing functionality.

Tasks:

1. Install jest, ts-jest, and related dependencies.
2. Configure jest.config.ts to support TypeScript.
3. Identify key modules or functions that require testing.
4. Create a tests folder or add .test.ts files for each module.
5. Write test cases to cover core functionalities, including edge cases.
6. Update workflows (if applicable) to include the test suite in the CI/CD pipeline.
7. Add a section in the README on how to run the tests locally.
8. Ensure a minimum of 80% code coverage for the current implementation.

Helpful Resources:

• https://jestjs.io/
• https://www.npmjs.com/package/ts-jest